Honda said Thursday that an exploding airbag in one of its cars killed a woman in Malaysia, bringing to five the number of deaths linked to a defect in parts made by embattled Japanese supplier Takata.

The previous four cases happened in the United States, but Honda said another woman died in a July crash after the rupture of a Takata-made airbag.

"An airbag on one of our vehicles exploded abnormally and a Malaysian woman was killed," said a Tokyo-based spokesman for the Civic and Accord maker.

At least three of the five deaths "were caused by an abnormal airbag explosion, including the latest case in Malaysia", Honda said, adding that the airbag's involvement in the other two cases had yet to be confirmed.

The news came as the car giant announced an additional recall of more than 170,000 vehicles worldwide due to the risk that an explosion could send metal shards from the airbag's inflator hurtling at drivers.

Police reportedly investigated at least one driver death in the US as a murder due to woman's grisly injuries, until their focus switched to the vehicle's airbag.

The National Highway Traffic Safety Administration (NHTSA), the US auto safety regulator, has expanded its "urgent" warning to owners of cars with affected airbags to take them to dealers to fix the problem.

Takata is facing the biggest test in its 80-year history with lawsuits, calls for a criminal probe, and accusations of "deception and obfuscation" over the potentially deadly defect.

Millions of vehicles produced by some of the world's biggest automakers, including Honda, Toyota and General Motors, are being recalled over the problem.

- Cover-up claims -

Honda has been named in a US lawsuit as a defendant, which alleges it conspired with Takata to hide the flaw for years.

Quoting former Takata employees, the New York Times has reported that secret tests were conducted a decade ago to investigate the issue, but executives ordered the destruction of data that exposed design flaws.

Takata's Tokyo-listed shares have lost about half their value since an investigation was opened in June.

Attention has focused on a Takata plant in Mexico, with suspicions the defect may be linked to a chemical propellant used to inflate the airbags which can more easily rupture in areas with high humidity.

On Thursday, the company confirmed that it had changed the chemical makeup of its airbag propellants, but insisted the move wasn't linked to design flaws.

"We constantly update our products -- it has nothing to do with the recalls," a Takata spokesman told AFP.

Takata has warned over a bigger-than-expected annual loss, but its top executives have stayed largely silent on the crisis.

Founded in 1933 as a textile company, Takata evolved into an automotive parts giant that started selling airbags in the 1980s and now has dozens of plants and offices in 20 countries, including the United States,China and Mexico.

The airbag division accounts for about 40 percent of its total revenue, which amounted to 556.99 billion yen ($4.88 billion) last fiscal year.

Major automakers have shied away from discussing their future relationship with Takata, but a quick switch is unlikely given the Japanese giant's foothold in the sector.

Still, parts sourcing for the 2019-2020 model years is happening right now, and a Toyota executive last month said the world's biggest automaker wants to replace the defective part "with something of better quality".